Torrential rain and gale-force winds caused by a cyclone have killed at least 21 people in southern Brazil, with more flooding expected, the BBC reported.
The governor of Rio Grande do Sul said it was the worst weather disaster in the state's history.
Thousands of people have been forced from their homes, officials said.
Bolivia is running out of natural gas, its main source of income, due to a lack of investment in exploration for new reserves, a senior official has said.
Since 2014, the country has seen a decline in production, the president of state oil company YPFB, Armin Dorgathen, told reporters in the eastern city of Santa Cruz.
"There were not a lot of exploration projects," he added.
Leaders of the BRICS emerging economies meet in Johannesburg this week looking to widen the bloc's influence and push for a shift in global geopolitics.
South Africa's Cyril Ramaphosa is expected to host China's President Xi Jinping, India's Prime Minister Narendra Modi and Brazil's President Luiz Inacio Lula da Silva for the annual three-day summit starting tomorrow.